The present invention relates to method for synthesizing a suspension of monodisperse tungsten nanoparticles. There are many existent metal nanoparticle syntheses. See: [1] Landstrom et al, “Characterization and modeling of tungsten nanoparticles generated by laser-assisted chemical vapor deposition: Journal of Applied Physics 95 (2004) 4408-4414; [2] Lei et al, “Synthesis of tungsten nanoparticles by sonoelectrochemistry”, Ultrasonic Sonochemistry 14 (2007) 81-83; [3] Xiong et al, “Synthesis and characterization of ultrafine tungsten and tungsten oxide nanoparticles by a reverse microemulsion-mediated method”, Chem. Mater. 18 (2006) 2211-2218; [4] Magnusson et al, “Single-crystal tungsten nanoparticles produced by thermal decomposition of tungsten hexacarbonyl”, J. Mater. Res. 15 (2000) 1564-1569; [5] Prasanta et at “Synthesis of tungsten nanoparticles by solvothermal decomposition of tungsten hexacarbonyl”, International Journal of Refractory Metals and Hard Materials 27 (2009) 784-791; and [6] (WO/20071030254) Methods of Producing Tungsten Nanoparticles. All of these, however, are either energy-intensive; are difficult to scale up; cannot produce monodisperse particles; and require the use of surfactants or other stabilizing ligands (which decrease the utility of the synthesized product). For instance, in order to get high loadings, such as 50 weight percent metal nanoparticles into an optically clear polymer without loss of optical properties, the nanoparticles must be sufficiently small and complete nanoparticle dispersion is required. In order to avoid the detrimental agglomeration, the polymer must chemically interact favorably with the metal nanoparticles. If the metal nanoparticle has a surface layer of surfactant, or other stabilizing ligand, then such a favorable interaction is difficult or impossible to achieve.
Tetrahydrofuran (THF) is chemically compatible with many systems, and is easily removed due to its relatively low boiling point. The ability to synthesize metal nanoparticles that are stabilized by only THF could enable production of high loading nanoparticle-polymer composites without sacrificing the original (desired) polymer properties.